allow for tag intersection queries on code list page

source/code/templates/code/code_list.html

@@ -1,12 +1,14 @@
 {% extends "code/_base_code.html" %}
 
+{% block page_title %}{% if tags %}Entries tagged: {% for tag in tags %}{{ tag.name }}{% if not loop.last %}, {% endif %}{% endfor %}{% endif %} - {{ super() }}{% endblock %}
+
 {% block content %}
 <h1 class="maintopic"><a href="{{ url('code_list') }}">Code</a>{% if tag %} / <span class="category">{{ tag.name }}</span>{% endif %}</h1>
 
 <div id="filterable-list">
-{% if tag %}
+{% if tags %}
     <div class="grouper-block filter-block">
-        <h2 class="grouper-header"><span class="category">Code index entries tagged: {{ tag.name }}</span></h2>
+        <h2 class="grouper-header"><span class="category">Code index entries tagged: {% for tag in tags %}{{ tag.name }}{% if not loop.last %}, {% endif %}{% endfor %}</span></h2>
         {% for code in object_list %}
         <div class="grid-box">
             <h3><a href="{{ code.get_absolute_url() }}">{{ code.name }}</a></h3>

source/code/urls.py

@@ -26,19 +26,19 @@
         name = 'code_list_feed_json',
     ),
     url(
-        regex = '^tags/(?P<tag_slug>[-\w]+)/$',
+        regex = '^tags/(?P<tag_slugs>[-\w\+]+)/$',
         view = CodeList.as_view(),
         kwargs = {},
         name = 'code_list_by_tag',
     ),
     url(
-        regex = '^tags/(?P<tag_slug>[-\w]+)/rss/$',
+        regex = '^tags/(?P<tag_slugs>[-\w\+]+)/rss/$',
         view = cache_page(CodeFeed(), 60*15),
         kwargs = {},
         name = 'code_list_by_tag_feed',
     ),
     url(
-        regex = '^tags/(?P<tag_slug>[-\w]+)/json/$',
+        regex = '^tags/(?P<tag_slugs>[-\w\+]+)/json/$',
         view = cache_page(CodeList.as_view(), 60*15),
         kwargs = {'render_json': True},
         name = 'code_list_by_tag_feed_json',

source/code/views.py

@@ -13,28 +13,32 @@ class CodeList(ListView):
 
     def dispatch(self, *args, **kwargs):
         self.render_json = kwargs.get('render_json', False)
-        self.tag_slug = kwargs.get('tag_slug', None)
-        self.tag = None
-
+        self.tags = None
+        self.tag_slugs = kwargs.get('tag_slugs', None)
+        self.tag_slug_list = []
         return super(CodeList, self).dispatch(*args, **kwargs)
 
     def get_queryset(self):
         queryset = Code.live_objects.prefetch_related('organizations')
 
-        if self.tag_slug:
-            self.tag = get_object_or_404(Tag, slug=self.tag_slug)
-            queryset = queryset.filter(tags__slug=self.kwargs['tag_slug'])
+        if self.tag_slugs:
+            self.tag_slug_list = self.tag_slugs.split('+')
+            # need to fail if any item in slug list references nonexistent tag
+            self.tags = [get_object_or_404(Tag, slug=tag_slug) for tag_slug in self.tag_slug_list]
+            for tag_slug in self.tag_slug_list:
+                queryset = queryset.filter(tags__slug=tag_slug)
 
         return queryset
 
     def get_context_data(self, **kwargs):
         context = super(CodeList, self).get_context_data(**kwargs)
         context['active_nav'] = 'Code'
 
-        if self.tag:
-            context['tag'] = self.tag
-            context['rss_link'] = reverse('code_list_by_tag_feed', kwargs={'tag_slug': self.tag_slug})
-            context['json_link'] = reverse('code_list_by_tag_feed_json', kwargs={'tag_slug': self.tag_slug})
+        if self.tags:
+            pass
+            context['tags'] = self.tags
+            context['rss_link'] = reverse('code_list_by_tag_feed', kwargs={'tag_slugs': self.tag_slugs})
+            context['json_link'] = reverse('code_list_by_tag_feed_json', kwargs={'tag_slugs': self.tag_slugs})
         else:
             context['rss_link'] = reverse('code_list_feed')
             context['json_link'] = reverse('code_list_feed_json')